The most comon cause of an engine that keeps revving up and down (aka surging) is a dirty air filter.
It keeps the engine from over revving.
You may have clogged jet in the carb, or in the small fuel filter. Check everything from the tank down to carb, and if necessary take carb apart.
It will only rev so far in park or neutral as the computer keeps the engine from revving too high without a load on it to keep from doing damage.
if it smokes just when started and then quits smoking, it may have to much oil in it, check oil level, if it keeps on smoking then you have a ring problem what TYPE of oil you have in it, When they are shipped there is oil injected into the bores through the spark plug holes, this will burn off for a while, so if it's new then it's no problem.
No! it only controls the air/fuel mixture at idle - it is by-passed when the engine revs-up. Generally, when there is a problem with the air control valve it causes the idle to become erratic and 'hunt' and maybe the engine keeps stalling.
There are two types, both on the camshaft. Lower HP (around 8HP or less) typically have a lobe with a bump on it that keeps a valve (often the exhaust) open at RPMS under 250, aiding in starting because the valve does not fully close) Larger engines have a counterweight on the cam that swings "up" at the same RPMs are "removes" the high spot achieving the same affect as above.
32:1 is the most common and the best ratio. It keeps the engine well lubricated during long rides, high heat conditions, and high revving rpm's.
EDC light keeps coming on my Mercedes c220 diesel and losing power at 3,500 revs,
Oil is not a coolant, it is a lubricant, but it keeps the engine lubricated to prevent friction, which reduces heat and makes is run cooler. Water in the radiator, and the radiator fan, is what keeps the engine cool.
Governor
fuel, fire, and compression
It prevents the liquid within the engine from freezing or boiling. Coolant does just what the name implies. It keeps the engine cool, meaning it keeps the engine at the correct operating temperature. It also prevents corrosion within the engine and cooling system.